It has been shown by Andre Lwoff that a small increase in temperature above the optimum can stop viral development and eventually lead to the destruction of a virus. A general review on temperature and viruses has been published in an article entitled "La Virulencia de Los Virus Y La Lucha del Organismo Contra La Infeccion Viral" (Spanish), Fundacion F. Cuenca Villoro Instituto de Investigacion Ulta Zaragoza, 1974. The present inventors are not aware, however, of applications of these theories to the treatment of the nasal mucosa, nor to the treatment of a common cold or allergic rhinitis connected with the nasal mucosa.
Various forms of apparatus are known for supplying heated and humidified air to patient for inhalation therapy. Examples of such apparatus are described in U.S. Pat. No. 3,903,883 to Pecina, U.S. Pat. No. 2,040,630 to Silten, U.S. Pat. No. 1,832,916 to Purdie, U.S. Pat. No. 742,244 to Sherburne, U.S. Pat. No. 865,021 to Dorment, Swiss Pat. No. 261,779, Austrian Pat. No. 150,117, U.S. Pat. No. 1,554,219 to Kitchen, U.S. Pat. No. 2,906,463 to Curry and British Pat. Nos. 1,490,974; 1,475,710; 1,448,473; 1,343,385; 1,294,808; 1,242,694; and 1,110,780.
The prior art apparatus of which applicants are aware and which is mentioned hereinabove is generally intended to supply air for inhalation purposes in response to a breathing in action by a patient and is not designed to provide a flow of humidified hot air to the nasal mucosa. In the examples where temperature controls are provided, they are intended to preserve a temperature range wherein no damage to the patient occurs and are not designed to maintain a precise temperature at the nasal passages. In none of the prior art apparatus is there a teaching or suggestion that such apparatus is suitable for treatment of the common cold, or for the treatment of allergic rhinitis. In fact, none of the prior art apparatus mentioned above is suitable for treatment of the nasal mucosa, allergic rhinitis or the common cold.
The temperature of the gas stream provided by prior art apparatus is too low to affect the viruses causing the common cold or to affect the conjugate factor leading to allergic rhinitis. Such apparatus is not suitable for heating the nasal passages and the nasal mucosa homogeneously at 43.degree. C. and without causing damage to the nasal mucosa.